Can't switch account and bind account.
Switch account = 500 Internal Server Error
Bind account = 404 Not Found
Lucky problem fix, factory reset for my phone. Because customer service also don't know about this, ask me to restart phone,but still same. After redownload again, still same. So I pick factory reset, everything fix.
To be honest, I've already encountered similar problems when I tried to do everything myself and thus save money. That was my fault. I'm currently working with namecheap specialists, you can find out more about this company here https://www.namecheap.com/hosting/dedicated-servers/ and the dedicated hosting they offer. I think it's a pretty good option.